Indicator detecting devices such as touch panels and the like have come into wide use, and various inventions relating to indicator detecting devices have been made. The inventors of the present application and others have previously made inventions relating to indicator detecting devices of a cross-point type capacitive coupling system capable of detecting a plurality of indication positions (multiple-point detection) indicated by a plurality of indicators such as fingers, and applications therefor have been filed by the applicants.
An indicator detecting device 1X of FIG. 11 represents an example of configuration of an indicator detecting device of the cross-point type capacitive coupling system. The indicator detecting device 1X has a sensor section 100. The sensor section 100 is formed by laminating a transmitting conductor group 11, an insulating layer, and a receiving conductor group 12 in order from a lower layer side. The transmitting conductor group 11 is formed by arranging a plurality of linear transmitting conductors 11Y1, 11Y2, . . . extending in an X-axis direction in parallel with each other in such a manner as to be separated from each other at predetermined intervals in FIG. 11. The receiving conductor group 12 is formed by arranging a plurality of linear receiving conductors 12X1, 12X2, . . . extending in a direction of intersecting the transmitting conductors 11Y1, 11Y2, . . . (Y-axis direction in FIG. 11) in parallel with each other in such a manner as to be separated from each other at predetermined intervals.
In the indicator detecting device 1X, a transmission signal supply circuit 21 supplies predetermined different signals to the respective transmitting conductors 11Y1, 11Y2, . . . in timing according to a clock signal from a clock signal generating circuit 22 according to control of a control circuit 40. Specifically, the transmission signal supply circuit 21 can supply signals of different frequencies to respective transmitting conductors (frequency multiplex system), or generate signals shifted in phase for respective transmitting conductors from a signal of a predetermined coding pattern and supply the signals shifted in phase (phase shift system), or supply signals of different code patterns to respective transmitting conductors (code multiplex system).
A receiving section 300 detects changes in current flowing through intersections (cross points) of the respective transmitting conductors 11Y1, 11Y2, . . . and the respective receiving conductors 12X1, 12X2, . . . at the respective cross points. In this case, at a position where an indicator such as a finger is placed on the sensor section 100, a current is shunted via the indicator, and thereby a change in current occurs. Thus, when the cross point where the change in current occurs is detected, the position indicated by the indicator on the sensor section 100 can be detected.
Specifically, as shown in FIG. 11, the receiving section 300 amplifies signals of the respective receiving conductors 12X1, 12X2, . . . in an amplifying circuit 31, converts the signals of the respective receiving conductors 12X1, 12X2, . . . into digital signals in an A/D converting circuit 32, and supplies the digital signals to an arithmetic processing circuit 33. According to control of the control section 40, the arithmetic processing circuit 33 subjects the digital signals from the A/D converting circuit 32 to arithmetic processing corresponding to the predetermined signals supplied to the respective transmitting conductors 11Y1, 11Y2, . . . , and thereby detects changes in current at the respective cross points.
For example, when the transmission signal supply circuit 21 is that of the frequency multiplex system, the arithmetic processing circuit 33 detects signals of target frequencies by performing synchronous detection operation using signals of the same frequencies as those of the signals supplied from the transmission signal supply circuit 21 to the respective transmitting conductors 11Y1, 11Y2, . . . . A position detecting circuit 34 operates according to control of the control section 40 to detect an indication position indicated by an indicator according to levels of the signals of the target frequencies.
When the transmission signal supply circuit 21 is that of the phase shift system or the code multiplex system, the arithmetic processing circuit 33 calculates correlation operation values corresponding to a target code by performing correlation operation using the code corresponding to the code supplied from the transmission signal supply circuit 21 to each of the transmitting conductors 11Y1, 11Y2, . . . . The position detecting circuit 34 operates according to control of the control section 40 to detect an indication position indicated by an indicator on the basis of the calculated correlation operation values.
Because the indicator detecting device of the cross-point type capacitive coupling system has the plurality of cross points on the sensor section 100, as described above, indication positions indicated by a plurality of indicators can be detected (multiple-point detection).
Patent Document 1 listed below discloses an invention relating to an indicator detecting device of the cross-point type capacitive coupling system using the frequency multiplex system. An invention relating to an indicator detecting device of the cross-point type capacitive coupling system using the phase shift system is disclosed in Patent Document 2 listed below. In addition, an invention relating to an indicator detecting device of the cross-point type capacitive coupling system using the code multiplex system is described in Japanese Patent Application No. 2009-288273 filed on Dec. 18, 2009.
Patent Document 3 and Patent Document 4 listed below disclose inventions relating to a multi-user touch system that detects contact positions of respective users on a touch surface when the plurality of users simultaneously touch the touch surface. For example, as shown in FIG. 12 of the present application, a multi-user touch system described in the cited Document 3 is of a table type including a display unit T200, a transparent substrate 410, a touch detecting element 420, a transparent conductive layer 450, and electrodes EA to ED. Though not shown in FIG. 12, the transparent conductive layer 450 is connected with a transmitter for supplying a predetermined signal to the transparent conductive layer 450, and a receiver is connected to each of the four electrodes EA to ED on a table top T100.
As shown in FIG. 12, each of users UA and UB brings a finger of one hand into contact with the transparent conductive layer 450 on the display screen of the display unit T200, and brings a finger of the other hand into contact with the electrode EA or EB near the user. In this case, a signal from the transmitter connected to the transparent conductive layer 450 is supplied to the electrodes EA and EB through the transparent conductive layer 450 and the bodies of the users UA and UB, and further supplied to the receivers connected to the respective electrodes EA and EB.
Therefore, when users are assigned to the respective electrodes EA to ED in advance, it is possible to detect which users are making a finger or the like touch the transparent conductive layer 450 on the display screen of the display unit on the basis of results of reception at the receivers connected to the respective electrodes EA and EB. Further, the contact position of the users on the touch detecting element can be detected through the touch detecting element 420.
In addition, a configuration opposite to the above configuration is possible. Specifically, transmitters for generating different signals are connected to the respective electrodes EA to ED, and the transparent conductive layer 450 is connected with a receiver. Then, as shown in FIG. 12, each of the users UA and UB brings a finger of one hand into contact with the electrode EA or EB near the user, and brings a finger of the other hand into contact with the transparent conductive layer 450 on the display screen of the display unit T200. In this case, a signal from the transmitter connected to the electrode EA is supplied to the transparent conductive layer 450 via the body of the user UA, and further supplied to the receiver via the transparent conductive layer. Similarly, a signal from the transmitter connected to the electrode EB is supplied to the transparent conductive layer 450 via the body of the user UB, and further supplied to the receiver via the transparent conductive layer.
Therefore, in this case, the contact position of the users UA and UB can be detected through the touch detecting element 420. When users are assigned to the respective transmitters connected to the respective electrodes EA to ED in advance, it is possible to detect which users are making a finger or the like touch the transparent conductive layer 450 on the display screen of the display unit according to the signals received by the receiver through the transparent conductive layer 450.